Heater of uniform specific loading



July 6, 1965 E. FEHR 3,192,907

HEATER OF UNIFORM SPECIFIC LOADING Filed Sept. 15, 1961 7 Fig. 3

United States Patent 3,192,907 HEATER Di UNiFtERli/Jl SPEQEFiC LQADEIS Eugen Fehr, Walliselien, Zurich, Switzerland AG. fiir @eir'euerungen, Winterthurerstr. 153/156, Zurich, Switzerland) Edited Sept. 15, 1961, Set. N 138,489 Qiahns priority, application Switzeriaud, Sept. 17, 1969,

16,533/69 1 Claim. (Ci. 122-225) causes a drop of the heat-transfer coefticient, the so-..

called K value, so that the decrease of the specific load of the heating face (B.t.u./sq.ft./h.) is influenced in a double sense, i.e. not only by the decrease in the temperature' difference.

The subject matter of my present invention are heaters in which the flow cross-section of the combustion gases is gradually restricted While they are progressively cooled, as far as possible so that their decrease in volume is overcompensated, i.e. that their velocity is increased thereby. The so-called K value (B.t.u./sq.ft./h./ F.) also is increased, however, so that the heat transfer, i.e. the specific load, may be held substantially constant.

One form of the present invention is shown in the form of an oil-fired sectional boiler adapted for conversion to coal-firing. In the drawing FIGS. 1 and 3 show a more or less schematical vertical section through the boiler, FIG. 1 being the version adapted for coal-firing, and FIG. 3 being the version adapted for oil-firing, and V FIGS. 2A and 28 showing horizontal sections EE and EE' respectively in FIG. 1. v

This continual decrease of the combustion-gas flow zone G by the lateral slant of the fuel or fire-chamber, brought about by the ribs Ri which taper-off upwardly, is so chosen in accordance with the invention that not only will be balanced the decrease in volume of the gases by cooling, but the gases will be accelerated yet.

Since in this arrangement a gas-generator effect and dry distillation may arise in fire-zone F and in the solid fuel, firing is carried out to advantage with excess air, i.e. so that the oxygen residual of the combustion gases above the fuel and in the upper portion of chamber G sutlices for possible afterburning. As the combustion air enters through ashpit A, it partly will flow through grate R0, as indicated by the arrows, partly however rise directly in space G, supply with oxygen the fire-Zone laterally adjacent to the ribs Ri and arrive as secondary air also in the space above the fuel B.

The heater shown in FIG. 1 is eminently suited for V amass? Patented July 6, 1965 oil-firing, but may readily be converted to cool firing. F1 denotes the oil-burner flame, Sp is the lateral lining of the fire-chamber with fire-clay plates, and Sg denotes the cover of the fire-chamber, comprising fire-clay vault bricks. In this arrangement, the fire-clay bricks 0 plates Sp are set up, i.e. leaned against the ribs, so as to seal as tightly as possible the gas-flow space G from the firechamber. The combustion gases of the flame F1 now are forced, as indicated by arrows, to first flow downwardly, then pass through the grate and flow, in accordance with the invention, through the tapering space G.

Owing to this passage of the combustion gases through the grate, the grate advantageously is Water-cooled, and j thereby will also represent a heating surface.

When it is desired to convert the boiler shown to coal firing, the refractory lining and vault bricks'Sp and Sg are removed. In such case, a portion of the combustion air rises from ashpit A through the water-cooled grate R0 to maintain combustion in the coal heap while another portion of the air rises through the fines G to pass partly into the coal heap laterally and partly as secondary air into the fire space above the coal heap.

What I claim as new and desire to secure by Letters Patent, is:

In a single-pass hot-Water heating boiler comprising water-containing boiler sections, a water-bearing grate integral with said sections, said sections forming between them fines of upwardly constantly decreasing cross-section laterally open to the inside, a firebox having upwardly diverging sides defined by said sections, an ashpit communicating with said fines, and top outlets for said flues, the improvement comprising removably assembled fireclay bricks lining the firebox sides and being set on edge loosely on top of each other, and a plurality of loosely and removably assembled arched fireclay bricks to form a vault bearing on the top edges of the brick lining.

References Cited by the Examiner UNITED STATES PATENTS PERCY L. PATRICK, Primary Examiner.

FREDERICK L. MATTESON, JR., EDWARD 1.

MICHAEL, ROBERT A. OLEARY, Examiners. 

